Effects of Er:YAG Laser Irradiation on the Microtensile Bond Strength to Bleached Enamel

Autor(es)

Leonetti, Eduardo dos Santos ^[1] ; Rodrigues, Jose Augusto ^[1] ; Reis, Andre Figueiredo ^[1] ; Navarro, Ricardo Scarparo ^[2] ; Correa Aranha, Ana Cecilia ^[3] ; Cassoni, Alessandra ^[1]

Afiliação do(s) autor(es)

^[1] Univ Guarulhos, Sch Dent, Dept Restorat Dent, BR-07023070 Sao Paulo - Brazil

^[2] Univ Camilo Castelo Branco, Sch Dent, Dept Restorat Dent, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Special Lab Lasers Dent LELO, Sch Dent, Dept Restorat Dent, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Photomedicine and Laser Surgery; v. 29, n. 8, p. 551-558, AUG 2011.
• Citações Web of Science: 8

Resumo

Objective: The objective of this study was to evaluate the influence of different Er:YAG laser (lambda = 2.94 mu m) energy parameters on the microtensile bond strength (mu TBS) and superficial morphology of bovine enamel bleached with 16% carbamide peroxide. Background: Laser irradiation could improve adhesion to bleached enamel surfaces. Methods: Sixty bovine enamel blocks (7x3x3 mm(3)) were randomly assigned to six groups according to enamel preparation procedures (n = 10): G1-bleaching and Er:YAG laser irradiation with 25.52 J/cm(2) (laser A, LA); G2-bleaching and Er:YAG laser irradiation with 4.42J/cm(2) (laser B, LB); G3-bleaching; G4-Er:YAG laser irradiation with 25.52 J/cm(2); G5-Er:YAG laser irradiation with 4.42J/cm(2); G6-control, no treatment. G1 to G3 were bleached for 6 h during 21 days. Afterwards, enamel surfaces in all groups were slightly abraded with 600-grit SiC papers and G1, G2, G4 and G5 were irradiated according to each protocol. Enamel blocks were then restored with an etch-and-rinse adhesive system and a 4-mm thick composite buildup was made in two increments (n = 9). After 24 h, restored blocks were serially sectioned with a cross-section area of similar to 1 mm(2) at the bonded interface and tested in tension in a universal testing machine (1 mm/min). Failure mode was determined at a magnification of x100 using a stereomicroscope. One treated block of each group was selected for scanning electron microscopy (SEM) analysis. mu TBS data were analyzed by two-way ANOVA and no statistical differences were observed among groups. Results: Mean bond strengths (SD) in MPa were: G1-30.4(6.2); G2-27.9(8.5); G3-32.3(3.9); G4-23.7(5.8); G5-29.3(6.0); G6-29.1(6.1). A large number of adhesive failures was recorded for bleached and irradiated enamel surfaces. Conclusions: Bleached enamel surfaces mu TBS values were not significantly different from those of unbleached enamel. Even though Er:YAG laser irradiation with both parameters had no influence on mu TBS for bleached and unbleached enamel, SEM analysis revealed that Er:YAG laser irradiation with 25.52J/cm(2) should not be recommended, as enamel ablation was observed, whereas irradiation with 4.42J/cm(2) did not promote any remarkable changes on enamel surface. (AU)

• Processo FAPESP: 07/06083-4 - Análise da resistência de união, nanoinfiltração e características ultramorfológicas das interfaces de união resina-dentina produzidas por cimentos auto-adesivos ao longo do tempo
• Beneficiário: André Figueiredo Reis
• Modalidade de apoio: Auxílio à Pesquisa - Regular